Various types of melanin (DOPA, 5-S-cystienyl DOPA, dopamine, DHI) at a range of sample pH values have been studied by W-band EPR. The greatly enhanced resolution at high frequency allows for the unique g-anisotropies of different melanins to be studied as a function of pH. Melanins which have essentially identical spectra at X-band can be distinguished at W-band. Different semiquinone anion radicals have been identified in different melanins under alkaline conditions. These semiquinone radicals are primarily due to dihydroxyindole groups that are well hydrated. Melanin also contains a set of free radicals which are not semiquinone or semiquinone imines and vary little with pH. These radicals are associated with the less solubilized or condensed portion of the polymer.